Press with electrically controlled collapsible air link



Oct 21, 1 w. ERNST EI'AL PRESS WITH ELECTRICALIIY CONTROLLED COLLAPSIBLEAIR LINK Filed Jan. '25; 1940 s Sheets-Sheet 1 J N i rr-- g ,4 2 a o O aM N 3 g 3 n s o H 14 3 0 4| 5 5 s L1 3 5: 3x t g d l 0 I0 m #9 L 2 .T' Jc :5

d" m 4 0') V a I 5 Inventors I H WALTER ERNST VICTOR 5.5mm HERBERT 5.BOOHER b PauL C. Pococx mini;

. Auornmya Oct. 21, 1941. w. ERNST ETAL 2,260,175

PRESS WITH ELECTRICALLY CONTROLLED COLLAPSIBLE AIR LINK Filed Jan. 25,1940 I5 SheetsSh eet 2 Jena Foam I Lab 1.2.2.

lnvzntors WRLTER ERNST .85 VlCTOR 5. SHAW HERBERTiBuuHER PAUL LPOCOUAMlornzys Oct. .21, 1941. w. ERNST ETAL 2,260,175

PRES S WITH ELECTRICALLY CONTROLLED COLLAPSIBLE AIRLINK Filed Jan. 23,1940 3 Sheets-Sheet 5 111mm WALTER ERN VICTOR 3. SHAW, HERBERT $.BO0HER,PAUL C.POCOCK,

av m CIA/101M045,

. inoperative to alter a collapsible switch operated by the ram at aPatent ed Oct. 21, 1941 um'rso STAT Es PATENT orrlcs rrmss wrrnsmc'rmcmr comonmn COLLAPSIBLE LINK Walter Ernst,

and Herbert 8. Booher,

aslignors to The Hydraulic poration, Inc.,-' W of Delaware ApplicationJanuary 2 11 Claims.

This invention relates to hydraulic press control systems, and inparticular, to systems for selectively .varyinglthe speed of travel ofthe ram at different portions of its stroke.

One object of this invention is to provide a hydraulic press'controlsystem with a press sup- Victor s. Shaw, Paul 0. Pocock,

Mount Gilead, Ohio,

Development Cor- DeL, a corporation 3, 1949, Serial No. 315,204

. control system, as set forth in the preceding obplied with'pressurefluid from a source regulated predetermined point in the stroke of theram to Jects, wherein the collapsible link is operated by pressurefluid, such ascompressed air, and is provided with an adjustable stopfor regulating the extent of slow-down of the ram by adjusting thedistance through which the link can 001- lapse and expand. 1

In the drawings: z y

Figure-1 is a diagrammatic view, partly insection, of a hydraulic presscontrol system with a collapsible linkcircuit arranged according to oneembodiment of the invention.

Figure 2 is a wiring diagram of the electrical circuit for controllingthe main solenoid and permit the pump flow-control member to shift to areduced delivery position so as to slow up the ram for a portion of itsstroke in one direction, means being provided for rendering the link thepump flow during the ram stroke in the opposite direction.

Another object is to provide a hydraulic control system having a presswith a ram operated by pressure fluid from a variable delivery pump,link being provided between the and the pump flow-control beingcontrolled by a solepress control rod member, this link -noidal valve incircuit with the main solenoid which operates the pump control so' thatthe solenoidal valve is incapable of energizationwhile the main solenoidis deenergized, thereby preventing the accidental collapsing of the linkduring the return stroke of the ram.

valve-operating solenoid-oi the collapsible link circuit. I v

Figure 3 is a longitudinal section 7 through the collapsible linkaccording to this invention, showing the adjustable stop arr ngement.

Figure 4 is an' enlarged pers tive view of .the cam forproviding a dwellduring the press slowdown period. v

Figure 5 is a diagrammatic view similar to that of Figure 1 butcomprising means for reversing the travelof the press platen in responseto a predetermined position thereof.

Figure 6 is a wiring diagram pertaining to the structure of Figure 5.

In general, the hydraulic press control system of the present inventionconsists of a press having a ram which is reciprocable by pressure fluidsupplied by a variable delivery pump, the flowcontrol member of which isactuated in at least Another object is to provide a hydraulic presscontrol system with a ram reciprocable by pressure fluid supplied from avariable delivery pump, the mechanism between the ram and the flow--control member of the pump including a collapsible link under thecontrolof a solenoidally operated valve, the valve solenoid being incircuit with the main solenoid for operating the pump control,- andadditionally controlled by a limit predetermined location in its stroke.

to provide a hydraulic press Another object is control system as set.forth in the preceding obiect, wherein the limit switch is actuated byacam having a dwell portion for controlling the duration of the slow-downperiod ofthe ram.

Another obict'is to provide a hydraulic press .one direction by a mainsolenoid. Connected between the main solenoid and the flow-controlmember of the pumpis a collapsible link operated by pressure fluid, suchas compressed air, and under the control of a solenoidally operatedvalve, the valve solenoid in turn, being under the control of a limitswitch operated by the ram at a predetermined location in its stroke.The valve solenoid is arranged in the same electrical circuitwith themain solenoid sothat it cannot be flow and an undesired continuation ofthe travel energized except when the main solenoid is energized.

This feature prevents the'accidental collapsing of the link during thereturn stroke of the ram which has hitherto occurred as the ramapproaches its neutral position and shifts the pump control to neutral.Hitherto, the accidental collapsing of the link as the pump controlappreached neutral caused a sudden resumption of of l the ram instead ofa halting thereof. This undesired travel 0! the ram past its haltingposi- 2,184,665, of'December. 26, 1939. Pivotaliy eon-L tion haspreviously caused damage tothe press, stripping collars and pins fromthe press control rod and breaking the control linkage, or othermechanism, and causing other damage by reason 01' the fact that the pumpcontrol has not moved to its neutral position as intended.

The present invention prevents this accidental 1 collapsing, and alsoprovides a control over the duration of time the link is collapsed byactuating the limit switch of the solenoidal valve by a cam having adwell portion thereon. Another feature of the invention is the provisionof an adjustable stop. within the collapsible link, this adjustable stopbeing arranged to control the 3 distance through which the linkcollapses and consequently thedistance through which the pumpflow-control member moves in reducing its delivery.

Referring to the drawings in detail, Figure 1 shows a press I0,hydraulically connected to the .opposite side being connected to thecoma reversible variable delivery pump H and having a collapsible airlink i2 interposed between the pump control and the main solenoid l3which operates the pump control and is connected to the press controlmechanism. Also 5' provided in the press circuit is a pilot pump l4 1 on ted to supply pressure fluid to the servomotor li. for shifting theflow-control member g of. the pump II. The hydraulic circuit also con- 1tains a main cylinder release and by-pass valve 1 16 of the typedisclosed and claimed in the Ernst Patent No. 1,956,758 of May 1, 1934,and

I forming no part of the present invention. Ad-

jacent the valve I5 is a surge valve l1 of the 1 type disclosed andclaimed in the Ernst Patent N0. 1,892,568 of December 27, 1932, andlikewise I forming no part of the present invention.

f A tonnage control or pressure-responsive 3 electrical limit switch 13is likewise provided f for regulating the pressure at which the pressIll is reversed and caused to perform a retraction stroke. Pressurereliet valves I9, 20 and 2| and 1 a check valve 22 are provided in theremaining portion of the hydrauliccircuit. A solenoidally .operatedvalve 23, controlledby a limit switch 24, is provided in the pneumaticcircuit controlling the collapsible link the compressed air ,suppliedtherefor being additionally regulated by a manually operated needlevalve 25. The

pump II is likewise provided with a safety cen- 1tering device 26, ofknown design, on the op-' positeside of the pump II from the servomotoriii, and its details form. no part of the present invention. Y

The press II- is provided with a main cylinder 33 having a main plunger3| reciprocable therein, and connected to a main ram'or platen 32 havinga platen arm 33 projecting laterally therefrom. The press I. likewisehas a reciprocable control rod 34 wltha collar 35 engage- 6o able by theplaten arm 33 at a predetermined position on its return stroke, and acollar 33 for actuating the pump control mechanism as hereinafterexplained.- A retaining collar .31 at the top of the control 34regulates the distance 65 through which the latter descends. The platenarm 33 on its outer end is provided with a bracket 33 carrying a cam 33for operating the limit switch 24.

g'lheservomotorllwhichahiftstheshlftr ns 70 or flow-control member ofthe reversible variabio delivery pump is under the control of aservomotor control valve rod-.43, irrthemanner Set 10111: in the Irnatapplication Ser. N0. 170,- 2'0, flied 0830b :1. 1m.

nected at 4| to the servomotor control valve rod 40 is a rocking lever42, having its fulcrum at 43 and pivotally connected at its opposite endto the pin 44 engaging the arm 45 on the cylinder 46 of the collapsibleair link l2. The plunger 41 of the latter is pivotally connected, as at48, to the rocking lever 49 having its fulcrum at 50 and pivotallyconnected at ii. to the ,link 52. The latter is pivotally connected at53 to the arm 54, mounted upon the shaft 55 upon which the rocking lever56 is also mounted. One end of the rocking lever 56 is provided with arounded yoke engageable by the collar 36 as the press pressed air supplyconduit 59. Also connected .to

the conduit 58 is thebranch conduit 60 running to one side of thesolenoidal valve 23, the opposite side thereof being connected to theair exhaust conduit 6i. The solenoidal valve 23 is operated by asolenoid 62 in circuit with the limit switch 24, ashereinafter'explained.

The cam 39 on the bracket 38 (Figure 4) may be made in a single piece,or-it may consist of three pieces 63, 64 and 65 clampedto the bracket38. The portions 63 and 65 are beveled and provide the entering andleaving portions of the cam 39, whereas the portion 64 is a dwellportion, the length of which regulates the duration of the slow-downperiod. These three portions are clamped to the bracket 38 by the screws86,-

61 and 68, respectively. By loosening the screws 66, 51 and 58 the dwellportion 64 may be removed and a longer or shorter dwell portionsubstituted. The limit switch 24 is provided with a contact arm 69 forengagement with the cam 39. T

The collapsible air link l2, as previously stated,

consists of a cylinder 46 having a projecting arm against an annularenlargement 16. The plunger 41 passes through a hollow plug 11, threadedas at 18 into the cylinder 4' and provided internally witha bored plug13 for retaining an annular oil seal element-3| in position. 0n theplunger 41 there is also mounted a stop collar 3|, secured thereto bythe set screw 32.. This stop collar engages the inner end wall of thecap 10 when the piston 13 moves to its extreme left-hand position.If,-however, the cap III is unscrewed a sufllcient distance the piston13 will be halted by the annular stop portion 33 on the inner end of theplug 11. The cylinder 46 is provided with threaded and ports 34 and 33.The port serves to receive' the end of the conduit 53, whereas the port33 receives a threaded plug 33, preferably with a drilled passagewaytherethrough (not shown) as a The right hand end of the cylinder 43 isprovided with an annular-ridge l1 88171118 new Patent, No. 16 tonl3.

- the automatic restarting switch I06 in the hydraulic'circuit, inaddition to the elements previously mentioned, the pump II is connectedby the conduits 88 and 89 to the upper and lower ports 90 and 9I of themain cylinder I0.

A branch conduit 92 runs from the conduit 89 to the main cylinderrelease and by-pass valve I6. from which the conduit 93 runs to the port94 in the upper end of the main cylinder I0. A branch conduit 95 alsoruns to the surge valve I1 to open the latter upon the return stroke ofthe press. The pilot pump I4 receives fluid fromthe surge tank 96through the conduit 91, and discharges pressure fluid through theconduits 98 and 99 into the servomotor I5. The branch conduits I and INrun from the endsof the servo- I motor I6 to the surge tank 86, and theexhaust conduit I02 runs to the surge tank from the pressure reliefvalve 2 I. The pressure-responsive tonnage control limit switch I8 isconnected by the conduit I03 to the port I04 in the upper end of themain cylinder I0, and is also provided with an exhaust conduit I05running to the surge tank 96.

forming a holding circuit for the operating coil II5 when thepush-button switch III is released after being momentarily depressed.The valve solenoid 62 contains an armature 63" for operating thesolenoidal valve 23.

The electrical control circuit (Figure 2) is energized from the mainpowerlines I20 and I2I' through the branch lines I22 and I23. One of thesemi-automatic contacts of the combined push-button. and selector switchI08 is connected to one contact of the push-button switch III by theline I24, from the other contact of which the lines I25 and I26 run tothe automatic restarting switch I06 and interlock contact of themagnetic contactor II4, from the other contact of The electricalcircuit, in addition to the main solenoid I3, the valve solenoid 62, thelimit switch 24 andthe tonnage control limit switch I8, also contains anormally open automatic restarting switch I06 (Figure 2) operated by theplaten as it nears the end of its return stroke and before the controlrod 34 has been raised a suflicient amount to shift the pump control toits neutral delivery position. The restarting switch I06 is ordinarilyactuated by the control rod 34 and may be shifted by its engagement withthe collar 31, or any other suitably located stop. As shown in Figure 1,the restarting switch I06 is mounted upon the bracket I01 which servesas a guide for the upper end of the control rod 34, but it may likewisebe mounted in any other suitable position. The automatic restartingswitch I06 serves to automatically reenergize the main solenoid I3 andplace the pump I automatically upon its forward delivery stroke as theplunger 3I nears the end of its return stroke. This feature enables thepress to be operated in so-called full automatic operation, wherein theplunger 3| and ram or platen 32 perform a-repeated number of working andreturn strokes without halting more than momentarily at the end of eachstroke.

when semi-automatic operation is desired so single working stroke strokeand then halts, is switched out of the circuit by the combinedpush-button and selector switch I08. -An additional switch I09 of thiscombined type is provided for selecting whether automatic operation orhand operation is to be employed, and is also used in its pushbuttonfunction for manually reversing-the press at any point in its cycle.Hand operation is employed when the electrical control circuit of Figure2 is deenergized and the press control rod 34 is raised manually by ahand lever (not shown).

The electrical that the press performs 2. followed by a single returncircuit likewise contains an oil temperature limit switch IIO (Figure 2)whichis shifted from its normally closed position to a circuit-breakingposition by a thermostat when the temperatureof the oil, or otherworking fluid, exceeds a predetermined maximum. The opening of the oiltemperature limit switch I I0 terminates the automatic operation of thepress. An additional forward push-button switch III is likewise providedas a safety feature, so that the operator must use both hands instarting the press.

order to indicate when the electrical circuit is enwhich the line I21runs to the tonnage limit switch I8. From the latter the line I28 runsto the combined push-button and selector switch I08, as does the lineI29 from the automatic restarting switch I'06. The tonnage limit switchI8 is connected by the line I30 to the operating coil II5 of themagnetic contactor II4, from the other end of which-the line I3I runs tothe combined push-button and selector switch I09. Be-

yond this the line I32 runs to the signal light II2, from which thelines I33, I34 and I35 run to the branch power. line I23 by way of theresistance II3. From the branch power line I22 the line I36 runs to theoil temperature limit switch IIO, beyond which the line I31 runs to thecombined push-button and selector switch I09. The valve solenoid 62is'connected by the line I38 to the branch power line I23, and by theline I39=to the platen-operated limit switch 24, beyond'which the lineI40 runs to one of the contacts of the contactor switch blade H8. Theline I4I runs from the same contact to the main solenoid I3, from whichthe line I42 runs to one contact of the contactor switch blade II1.

It will be noted that on the return stroke of .the press ram theservo-motor on the pump is includes the air link 46 moves theservo-motor. control rod 40 to place the pump on neutral.

Withoutair pressure in the air link 46 no movement can be transmittedthrough the linkage and, therefore, the pump remains at full stroketending to force the ram beyond its upper limit, with the correspondingdamage to control linkage.

In Figure 1 it will be noted that an air cylinder I43 is in connectionwith the pipe 59. In this cylinder is a piston I44 and a piston rodI'45. The piston is spring pressed upwardly by spring I46, the lower endof piston rod I45 engages the roller I41 of the switch arm I48 of theswitch I49 which controls the circuit included within the wires I50 andI5I. The wire I50 is connected .to a terminal I52 which is adapted to beengaged by the motor starting switch I53.-- The other side of theterminal I52 is connected v to a wire I54 to the terminal I55. This is apart of a holding circuit which consists of'the wire I2I, wire I56,terminal I51, blade I58 to the 'wire i 32. nished to the compressed airsupply line 69 and ,flowsthrough the needlevalve 26 and the conduit 66,into the left-hand end of the collapsible of which is connected to themain line wire I20 and the other side of which is connected by the,

wire I62 to the terminal I63 engaged by the v motor stop switch I64, theother side of which is connected to the terminal I66 and, wire I6I,

' which is in turn controlled by the switch I69- Returning to the"switch arm I59, the lines I20, I2I. and I2Ia are connected to the motor10 lines I66, I61 and I68 of the motor I69 by the A switch blades I10,HI and I12.

' In operation the switch I49 is normally closed by the air pressure inthe line 69. r In the event of failure of that air pressure, the spring615 will move up the piston rod I45 permitting the switch I49 to openunder the influence of a spring I49a. The air pressure acts against thespring pressure or spring I46 to hold'the plunger at full strokeposition. With the, plunger air operated as above, the limit switch I49in series with the stop button I64 for themain motor circuit will beheld closed. On the failure of the ai or loss of 'air pressure, thespring I46 will ret the plunger I I46 to. its opposite position allowingle '25 closed limit switch I49 to open to press the ed a trol circuitto the motor I69 in the same manner\ as when the stop button I64 ispushed.

Operation In the operation of the press control circuit of thisinvention the pumps II and I4 are first started in operation. To causethe ram 32 to execute a working stroke, the operator momentarilydepressesthe switches I06 and III. If 35 semi-automatic operation isdesired the switch I08 is locked in engagement with thelower orsemi-automatic contacts. Under thesecircumstances the contactor coil H6is energized from the branch power line I23 by way of the lines I36 andI26, the push-button switch II I; the line I24," the switch I06, thelines I28 and I30, the contactor winding II6, the line I'3I, the switchI09 (assuming, of course, that it is set for automatic' operation), theline I31, the oil temperature limit switch I16 and the line I36 to thebranch power line I22.

The normally open magnetic contactor H4 then closes so that its switchblades H1 and H6 energize the main solenoid I3. -The interlock switchblade H9, in closing, operates a holding circuit which maintains theenergization of the 1 magnetic contactor winding -I'I6 even when theforward push-button switch I is released. The

energization of this holding circuit is maintained 55.

from the branch power line I23, through the line I36, the now closedswitch blade N8, the line I21, the tonnage control limit switch I8, theline I38, the contactor winding II6, the line I3I, the switch I69, theline I31, the oil temperature no limit switch H0 and the line I36 to thebranch power line I'22. The valve solenoid 62, however,

as yet remains 'unenergized since the normally open limit switch 24 hasnot yet closed by reason of the descent-of the platen or main ramMeanwhile compressed air has been furair link I2. This compressed airpushes the pis- 7 ton head 13 to the right, shortening the distance 0between the 1 pivotpins' and 46. noidal valve 23, however, remains inits normally closed position since its solenoid 62 has not yet 4 beenenergized.

The soleeans The energization of the main solenoid I3, as

described above, pullsdown its armaturel61 and rocks the rock shafts 56and 49 (Figure 1), shifting the collapsible link I2 to the left androcking the lever 42 to-cause the servomotor control valve rod 40 tomove to the right towards the servomotor I5. This action shifts theshift ring or flow-control member of the variable delivery pump II andplaces the latter on stroke so that it delivers pressure fluid by theconduit 66 to the upper endof the main cylinder I0, and withdraws fluidfrom the lower end thereof throughthe conduit 89. The consequent descentof the main plunger 3|. and ram 32 causes the cam 38 to engage thecontact member 69 of the limit switch 24 so that the latter is closedand energlzes the valve solenoid 62 since the latter is .electricallyconnected through the lines I36 and I40 to the already energized mainsolenoid I3. The solenoidal valve 23 then opens, permitting compressedair to escape through the conduits 68 and from the left-hand end of thecollapsible link cylinder 46. the cylinder 48 then move relatively toone another so as to increase the distance between'the pivot pins .48and 44. This permits the servomotor control valve rod 40 to shift towardits reduced delivery posiiton, moving the shift ring of the pump IItoward its reduced delivery position and consequently slowing down; thespeed of the main plunger 3I and main ram or platen 32.

Meanwhile, the main ram 32 continues to descend, and the contact member69 'of the limit .switch 24\ rides along the dwell portion 64 until itarrives. "at the beveled portion 63, when it is permitted to swing backto its normally open position. The opemng of the switch 24 deen-.ergizes the valve solenoid 62 and closes the solenoidal valve 23. Airfrom the air supply conduit 69 then passes through the needle valve 26and replenishes the air in the left-hand end of the cylinder 46, causingthe pistons 13 and cylinder 46 to'move again into their contractedposition with the pivot pins 44 and 48 at their minimum separations. i

The consequent shifting of the servomotor control valve rod-immediatelyshifts the pump shift ring or flow-control member toward an increaseddelivery position, increasing the discharge of pressure fluid'to themain cylinder I6 and speeding up the descent of the main ram 32. Thelatter then completes its working stroke. whereupon the building. up ofpressurein the main cylinder I 0 by engagement of the main ram 32 withthe workpiece, causes the normally closed tonnage control limit switchI6 to open, breaking the holding circuit of the magnetic contactor coilII6 by opening the circuit between the lines In and I30-(Figure 2).

The opening of the magnetic contactor II4 immediately deenergizes themain solenoid I3;

whereupon a spring (not shown) within the servomotor I6 shifts theservomotor control valve rod 40 to its reversed delivery position. The

variable delivery pump II then delivers pressure; fluid through theconduit 69 to the lower end of the main cylinder I0, and exhausts fluidfrom the upper end through the conduit 86. The main cylinder release andby-pass valve I6 operby-Dass the iiow'of the pump ates to momentarilywhile releasing pressure fluid from the upper end of the main cylinderI6 at the instant of reversal, as described in'the previously mentionedp atent disclosing and claiming this device; at

The piston head 13 and the same time the surge valve I1 is forciblyopened, as described in the previously mentioned patent disclosing andclaiming it.

The rise of the main plunger 3| and platen or ram 32 causes the cam 39to close the normally open limit switch 24, but nothing happens sincethe main solenoid I3 is deenergized by the opening of the magneticcontactor Ill.

4 Consequently, there is no danger of the operation of the collapsiblelink I 2 on the return stroke of the main plunger 3|. The main ram 32continues to rise untilits arm 33 engagesthe collar 35 and lifts thecontrol rod 34, causing the collar 33 to engage and rock the lever 56and shift the servomotor control valve rod 40 to its neutral positionthrough the motion of the intermediate linkage. The pump N then operatesat zero delivery, but immediately goes upon stroke at any tendency ofthe main plunger 3| to descend. In this manner the main plunger 3| isheld at the top of its retraction stroke.

At this point in full automatic operation, however, since the operatorhas previously moved the switch I to its full automatic position, thelimit switch I00 is closed by the rise of the control rod 34 andreenergizes the coil of the magnetic contactor I by way of the branchpower line I23, the lines I35, I26 and I25, the limit switch I08, theline I20, the switch I00, the lines I28 and I30, the coil II5, the lineI3, the switch I09, the line I31, the oil temperature limit switch III)and the line I36 to the branch power line I22.

The main solenoid |3is thus reenergized and shifts the servomotorcontrol rod 40 toplace the pump upon its forward delivery stroke, caus-1 ing the main plunger 3| to commence another working stroke with but amomentary halt at the top of its return stroke. The repeated operationofthe valve-operating solenoid 32 and the collapsible link I2 takesplace in the manner previously described upon each working stroke, butis prevented from taking place upon the return stroke by the fact thatthe main solenoid I3, with v which the valve solenoid 62 is in circuit,is deenergized. The press is halted by the operator when the operatordepresses the switch I09 or automatically by the oil temperature limitswitch 0 if the oil temperature rises to an undesired height.

The invention is, of course, not limited to presses in which the travelof the press platen is reversed in response to a'predetermined pressureacting thereupon, but may as well be used in connection with presses inwhich the reversal of the travel of sponse to a predetermined point oftravel of the platen. To this end, with reference to Figures 5 and 6,the platen 32 may, ata predetermined point of its pressing stroke and bymeans of a cam I15, open the switch Ila, which takes the place of switchI0 in the circuit of Figure 2. v 5

Opening of the switch |8a breaks the holding circuit for solenoid 5(Figure 6), thereby en-.

abling the spring in the pump II to move the latter to full deliveryretraction stroke position.

Since otherwise Figures 5 and 6 fully correspond to Figures 1 and 2, thecycle will then continuein the press platen is effected in recombinationwith reversible hydraulic motor means having a reciprocable ram and asource of pressure fluid therefor with a flow-control member forreversibly controlling the distribution of pressure fluid to saidhydraulic motor means, of means including an electrical device forreversibly moving said flow-control member between its forward deliveryand its reverse delivery positions through its neutral deliveryposition, said flow-control-member-moving means including an expandingand collapsing link device, electrical means for effecting the operat onof ,said link device, means responsive to the travel of said ram to apredetermined location for energizing said electrical means to effectthe operation of said link device to shift said flowcontrol member in adelivery-reducing direction, and means for deenergizing said electricalmeans near the end of the travel of said ram in one direction and formaintaining said electrical means deenergized during the oppositedirection of travel of said ram.

2. In a hydraulic press control system, the combination with reversiblehydraulic motor means having a reciprocable ram and a source of pressurefluid therefor with a flow-control member for reversibly controllingthedistribution of pressure fluid to said hydraulic motor means, ofmeans including an electrical device for reversibly moving saidflow-control member between its forward delivery and its reverse defordeenergizing said electrical device near theend of the ram travel in onedirection whereby to concomitantly deenergize said electrical means, andfor maintaining said electrical means deenergized during the oppositedirection of travel of said ram.

-3. In a hydraulic press-control system, the

combination with reversible hydraulic motor means having a reciprocableram and a source of pressure fluid therefor with a flow-control memberfor reversibly controlling the-distribution of pressure fluid to saidhydraulic motor means, of means including an electrical device forreversibly moving said flow-control member between its forward deliveryand its reverse delivery positions through its neutral deliveryposition, said iiow-control-member-moving means the manner described inconnection with Figures 1 and 2 It will be understood that-it is desiredto cominvention.

Having "thus fully described the invention,

including an expanding and collapsing link device, electrical means foreffecting the operation of said link device connected in circuit withsaid electircal device for moving said flow-control member, meansresponsive to the travel of said ram to a predetermined location forenergizing said electricalmeans to effect the operation of said linkdevice to shift said flow-control member in a delivery-reducingdirection, and means responsive to the attainment of a predeterminedpressure in said motor means near the end of the ram travel in onedirection for deenergizing said electrical device and concomitantlydeenergizing said electrical means and for maintaining said electricalmeans deenergized during the opposite direction of travel of said ram.

4. In a hydraulic press control system, the

' combination with reversible hydraulic -motor means having areciprocable ram anda source of pressure fluid therefor: with aflow-control member for reversibly controlling the distribution ofpressure fluidto said hydraulic motor means,

of-means including an electrical device for; reversibly moving saidflow-control member between its forward delivery and its reversedelivery positions through its neutral delivery posi tion, saidflow-contuol-member-moving means including an expanding and collapsinglink device, means for supplying pressure fluid to said 1 link device tooperate the same, avsolenoidal valve connected to control the supply ofpressure fluid in said link device, the solenoid of said valve beingconnected in circuit with said electrical device, means responsive tothe arrival of said ram at a predetermined position for energizing saidsolenoidal valve to actuate said link device, and means responsive tothe attainment of a predetermined pressure in said hydraulic motor meansfor concomitantly deenergizing said electrical device and said'solenoidal valve.

5. In a hydraulic press control system, the

combination with reversible hydraulic motor means having a reciprocableram and a source of pressure fluid therefor with a flow-control memberfor reversibly controlling the distribution of pressure fluid to saidhydraulic motor means, of means including an electrical device forreversibly moving said flow-control member between its forward deliveryand its reverse delivery positions through its neutraldelivery position,moving means including an expanding and collapsing link device, meansfor supplying pressure fluid to said link device to operate the same,means responsive to the arrival of said arm at l a predeterminedposition for lay-passing the supsaid flow-control-member cal devicesandfor maintaining the same dc energized during the retraction stroke ofthe P 7. In a hydraulic press control system, the combination withreversible hydraulic motor means having a reciprocable ram and areversible 'variable delivery pump'with a. flow-control member forreversibly varying the pump delivery from a forward delivery positionthrough a neutral position to a reverse delivery position, of a presscontrol element connected to said flow-control member and engageable bysaid ram, a solenoid operatively connected toshift said flow-controlmember, an expanding and collapsing link device connected between saidsolenoid and said flow-control member, fluid pressure-operated meansincluding a solenoidal control valve for actuating said link device,means responsive to the arrival of said rain at a predetermined loca-'tion on its stroke in one direction for operating saidsolenoidal valveto actuate said link device and shift said flow-control member in adelivery-reducing direction, means for deenergizing said solenoid toshift said flow-control member to its reverse delivery position, andmeans responsive to the deenergization of said solenoid for deenergizingsaid solenoidal valve.

8. In a hydraulic press control system, the combination with reversiblehydraulic motor means ,having a reciprocable ram and a reversiblevariable delivery pump with a flowcontrol member for reversibly varyingthe pump delivery from a forward delivery position through a neutralposition to a reverse delivery position, of yielding means for urgingsaid flowcontrol member into a reverse delivery position, a solenoidadapted when energized to urge said flow-control member. into a forwarddelivery position, an expanding and collapsing link device connectedbetween said solenoid and said a flow-control member and operable whenactuply of pressure fluid to said link device to actuate the same, andmeans responsive to the attainment of a predetermined pressure in said imotor means for altering the energization of said electrical device toshift said flow-control member into its reverse delivery position, andmeans responsive to the alteration of energizetion of said electricaldevice for rendering said by-passing means inoperative.

6. In a hydraulic press control system, the

combination with reversible hydraulic motor means having a reciprocableram and 'a reversible variabledelivery pump with a flow-control memberfor reversibly. varying the pump delivery from a forward deliveryposition through a neutral position to a reverse delivery position, 3 ofyielding means for urging said flow-control member in one direction, .anelectrical device for moving said flow-control member in the op- 1posite direction, an expanding and collapsing link 1 device connectedbetween said flow-control member and said electrical device, meansresponsive I to the arrival of said ram at a. predetermined location onits forward stroke for actuating said link device to effect the movingof said flow-con- 1 trol member to a reduced-delivery position; 1 meansfor supplying pressure fluid to actuate. 3 said link device, a valvefor-controlling said sup- 1 plying means, a secondelectrical device foroperating said valve, and means adapted to be actuated near the end ofthe forward stroke of i said ram for deenergizingboth of said electril5ated to eifect the shifting ofsaid flow-control member to a reduceddelivery position, electrical means for controlling the'actuation ofsaid link device, means responsive to the arrival of said ram at apredetermined location for operating said electrical means toactuatesaid link device, means responsive'to the travel of said ramuponits forward stroke for deenergizing said solenoid to reverse thedelivery of 'said pump, and means responsive to the deenergization ofsaid solenoid for concomitantly deenergizing said electrical means.

I 9 In a hydraulic press control system, the

combination with reversible hydraulic motor means having a reciprocableram and a reversible variable delivery pump with a flow-control memberfor reversibly varying the pump delivery from 0 a forward delivery.position through a neutral means for supplying pressure fluid to actuatesaid link device-anelectric motorfor driving said pump, and meanscontrolled by'the fluid v pressure actuating said link whereby, upon amember in one direction,

failure of said fluid pressure, said motor will be rendered inoperative.

10. In a hydraulic press control system, the

a neutral position to a reverse delivery position,

of yielding means for urging said flow-control moving said flow-controlmember in the oppositedirection, an expanding and collapsing link deviceconnected between said flow-control member and said electrical device,means responsive to the arrival of said ram at a predetermined locationon its forward str'oke for actuating said link device to effect themoving of said flow-control member. to a reduced-delivery position,means for supplying'pressure fluid to actuate said link. saidsupplylngmeana'a second electrical device for operating said valve,means adapted to be an electrical device for device, a valve forcontrolling actuated near the end of the forward stroke of said ram iordeenergizing both of said electrical devices, and for maintaining thesame deenergized during the retraction stroke of the ram; a motor foroperating said pump, and means controlled by the fluid pressureactuating said link to control the operation of said motor whereby, upona failure of said pressure, said motor will be rendered inoperative.

11. A hydraulic press comprising in combination a press ram, means 'forsupplying pressure fluid to said ram for actuating the same, electricmeans for driving said fluid supply means, link means including a fluidpressure chamber'oper able to vary the delivery of said pressure fluidsupply means, and means adapted in response to 'a predetermined pressurecondition in said chamher to prevent said driving means from furtherdriving said pressure fluid supply means. wan-ran ERNST. VICTOR S. SHAW,

PAUL (J. Pococx. nnnnna'r 8. 500mm.

